South Africa will not be rushing Heinrich Brussow back into action after the flanker sat out training on Tuesday.

The Cheetahs openside last played for the Springboks in November 2009 and coach Peter de Villiers said the backrow's fitness was being closely monitored. "We're being especially cautious with Heinrich," de Villiers said. "Every time he has come back from injury he has been pushed back too early and maybe we did the same with him last week. So we're happy to be over-cautious now - he is a valuable player and we can't let him rest enough. I'm hopeful he can play but I won't push him because he is one of those players that you build a team around."

De Villiers, however, is hopeful that Johann Muller and Coenie Oosthuizen will be fit to travel with the Springboks despite sitting out training on Tuesday. Lock Muller and prop Oosthuizen are both selected in the Springboks' 27-man squad for the away ties in the Tri-Nations but have sat out training since Thursday with a hamstring strain and a sprained ankle respectively. However, despite this, de Villiers insists the backroom staff are just being cautious.

"Coenie is still nursing his ankle," said De Villiers. "He was tested this morning and came through and he'll be OK. Johann should be fine - we're just being cautious with injuries."

CJ van der Linde, who was added to the squad as injury cover for Oosthuizen on Monday, took part in training on Tuesday and impressed de Villiers. "CJ has surprised me," said De Villiers. "He came through yesterday morning's fitness session very well and has trained again today so he is looking good. He'll train again tomorrow and then we'll make a decision." Gerhard Mostert also joined the squad on Monday as cover for Muller. South Africa open their Tri-Nations campaign against Australia in Sydney on July 23.